Network operators have provided methods for enabling privileged people to access the mobile network services by overriding any existing call connection, for instance in cases in which the mobile network suffers from congestion due to a critical event.
In particular, service providers, based on the subscriber's need, set a maximum precedence level of the subscriber at the subscription time. When accessing the mobile network, the subscriber can select a precedence level up to and including the maximum precedence level he has subscribed to, on a per-call basis. According to the precedence level, the subscriber can benefit of a priority over other subscribers for accessing the same service or for an existing call directed to the same destination.
The enhanced Multi-Level Precedence and Pre-emption service (eMLPP) is currently used in mobile telecommunications networks for providing different levels of precedence for call set-up and for call continuity in case of handover. The technical specification of the eMLPP service is disclosed in 3GPP TS 23.067, v.6.1.0, which is hereby incorporated by reference.
A pre-emption service may regard a resource or a called party. In a resource pre-emption, a call of a low priority user can be terminated so that resources can be made available for a call of higher priority. A called-party pre-emption can be decided by the subscriber and can consist in terminating a call to a particular user when a higher priority call from the subscriber is directed towards that specific user.
There are seven eMLPP priority levels which, in descending order, read as A, B, 0, 1, 2, 3 and 4. A and B are internal values of the Mobile Switching Centre and are mapped to value 0 when sent over signalling protocols. Value 4 represents the lowest priority level.
The MSCNLR node for mobile originating and mobile terminating calls allocates the priority that is provided to the radio access network and to the core network. If a priority has been allocated to the originating subscriber of the call, this priority is also applied for the connected terminating subscriber.
In mobile-originated calls, the priority level depends on the calling subscriber. If the user has no eMLPP subscription, the call shall have a default priority level defined in the network, if the network supports the service. Otherwise, if the user has an eMLPP subscription, the call shall have the priority level selected by the user at set up or the priority level predefined by the subscriber as a default priority level upon registration.
In mobile-terminated calls, the priority level depends on the calling party. If the call is not an ISDN MLPP call, i.e. no priority level is defined, the call shall be treated in the mobile network with a default priority level. If the call is an ISDN MLPP call, the call shall be treated with the priority level provided by the interfacing network.
As regards mobile-to-mobile calls in the same network or in case of roaming, the priority is treated for the calling subscriber as for mobile originated calls and for the called subscriber as for mobile terminated calls.
Information concerning the maximum priority level that a subscriber is entitled to use at call establishment is stored in the Home Location Register (HLR).
If the provisioning state for eMLPP is set to “Provisioned” then, when the subscriber registers with a Visitor Location Register (VLR), the Home Location Register (HLR) sends information about the logical state of eMLPP, the maximum priority level and the default priority level to the VLR, which stores such information.
The priority level, or level of precedence, and some other eMLPP parameters are carried in the signalling protocol, e.g. ISUP, for intra- and inter-network communications.
An intelligent network (IN) is a telecommunications network wherein intelligence is taken out of a switch and placed in a controller that then provides the logic for the IN and thus the intelligence. This separation provides the network operator with the means to develop and control services more efficiently and allow to introduce new capabilities more rapidly into the network. Once introduced, services can be easily customized to meet individual customer's needs.
Customised Application for Mobile Enhanced Logic (CAMEL) is an IN feature that provides mechanisms to support services of operators that are not covered by standardised services when roaming outside the Home Public Land Mobile Network (HPLMN). A Service Control Point (SCP) such as a GSM Service Control Function (gsmSCF) is the functional entity containing the CAMEL logic.
A drawback of current CAMEL networks is that the gsmSCF cannot interact with the eMLPP-defined level of precedence, regardless of whether the subscriber is roaming in a partner network or is using the network of his own operator.
Moreover, the priority assigned at dialogue level for the branch of the call toward and from the current gsmSCF is not derived from the eMLPP precedence level already established for that process.
In summary, there exist no methods or systems that allow to handle a call in an Intelligent telecommunication network according to a priority already set for this call or according to priority information available within the IN network or to handle communication between nodes in an intelligent network according to those aforementioned priority information.